Fermentation Temp - Chest Freezer

Can a chest freezer be used with a temp controller to maintain fermentation temps or is the cooling in a chest freezer to extreme?

Thanks

 

Many of us use a chest freezer with a temperature controller. Works great.

 

I use a chest freezer with temp control probe taped to the side of the fermenter covered in bubble wrap.

 

We have the temp probe in a 1 gallon plastic water jug filled with Star San. We ferment in corney kegs. We have done about 29 batches so far with no problems.

 

I've got my temp probe in a gallon of plain water. Star San would make more sense. I'll have to rectify that tomorrow...

 

I'm considering chest freezer for fermentation control. I'm wondering why put the probe in a gallon jug with starsan?

I've read taping the probe to the side of the carboy & cover the probe with insulation.

Or I've also seem thermowells...

 

Wouldn't the water jug be colder than the fermenter since yeasties aren't doing their thing? Or no because the cooler counteracts that?

 

do you want to measure ambient or fermenter temperature? the jug of water will measure ambient.

 

Ok sounds good. I bought a chest freezer, temp control and thermowells for my carboys. I'm done with the chilled wet tee shirt style ... Just wanted to make sure nobody has had any bad experiences with a chest freezer chilling to quickly and freezing wort and yeast on the surface.

I agree that a jug of starsan or water is not going to give you the accuracy. Fermenting yeast generate a lot of heat. Thermowells are the only way to be truly accurate. Making sure that the center of the vessel is the temp you want. Plus, probes don't like to sit in liquid.

Thanks for the info...

 

in active fermentation the fermenter would act as a heat source inside the fridge and could easily be at a higher temperature than the jug.

 

Be careful with the thermowell as its been reported to make the chest freezer over shoot. From what I've read on here, the consensus is taping the probe to the side and then insulating with bubblewrap works the best.

 

No, putting the probe in a jug of water does not accurately measure wort temp. The wort will be a little warmer during active fermentation. In the same way, if I have two batches fermenting at the same time, the one that's fermenting more actively will be warmer than the other. There's going to be innacuracy either way. So, I make some compromises and adjust the temperature controller accordingly. Also, even if I've only got one batch in, it's a little easier than taping & covering - it's a permanent solution.

As for probes not liking to sit in liquid... I don't care about their feelings.

 

May be semantics.. but, I'd say
Suspending the probe in the chest/box would be ambient.
Suspending the probe in a bottle of StarSan or water will closely approximate the temp in the FV. Yes, the yeast activity will raise the temp a bit.. but I believe the surface area of the FV will help keep that to a minimum. I'm not anal about a couple degree fluctuation.

The main benefit to suspending in liquid is that the compressor won't be going on/off a lot. The liquid acts as a thermal buffer. Else the ambient temp will go low and back to a high temp before it cuts back in. This way the compressor won't come back on until the liquid itself says.. "cool me down"

I don't have my chest in the house yet.. but, in the meantime, I put my FV in a large plastic rope handled bucket filled with water. That helps buffer the FV contents from the room changes that occur throughout the day.. especially in the summer. If the day gets too warm, I just drop a couple of frozen water bottles in the bucket to keep it in the fermenting range, which for me is between 62-65*F

Comments???

 

The thermowell works great (IMO) providing the temperature of the beer is not more than 2 degrees above the required temperature. (2 degrees is a guess). I place the sensor in the thermowell and leave it for about 10 minutes, then read the temperature off the controller. If the beer is more than 2 degrees too warm, I raise the sensor to the top of the thermowell. I find that this prevents the overshooting that veritas mentioned. Once the temperature has dropped to within one or two degrees of the required temperature, I drop the sensor to the bottom, and don't have any problems.

-a.